From patchwork Tue Dec 6 14:47:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13065921 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 501C1C4708C for ; Tue, 6 Dec 2022 14:50:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=rimsbA/qvGYc2ybiFKhLoceOYdZJRgFyKJZFaApoPcg=; b=IUQ74WXI/5DHPm RqCv7IPRLLhzpShFFdxFO+BLYGVtra4kQs9JBHBtzWzu2zf14QLxhPCxtdmFVxqa3/YNV45+t2tnY IyRKW4Qt42Z1eNLARuAWstLKv7tX4zgCzDzymFhVUsP22Uefsg/dJAXK6R4W4KOX6yd9WJ+QG4iQS LzUKvjf8pK0CizUNpZamtv/m93oTE6P8h4tZSgUr4PmUQtUX0IqoCDZtlahFWdQ2ZCPrXngWkX7uN POpyDv8v8geizt75wE5Z2UNiDCZg01q1Xplg+4wa4KauBj1eXvZ4reep/3YPhkpjEtL1dE3fhBjRB NZZ6Y7LY8pLKYW9zDNCw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p2ZFE-00BgyO-Nc; Tue, 06 Dec 2022 14:48:28 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1p2ZEy-00BglS-9S for linux-arm-kernel@lists.infradead.org; Tue, 06 Dec 2022 14:48:16 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1670338091; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JBNIGuT912oU9TwfpgZYupWQSbPpBbUlZPF7ZwOTGnM=; b=ffVbQ+TbSRhW3mzxRqUS5QSHzPnTU27L0ipz/Pnh7PVhUaLtIeAQBBFKzv7aVV98N95ZtC ZPuJPRngbVdTGBsREe+vOUaVvHAIdhIaWrQJx8nrQQh0V1PJwXdoInNIrIy21SYCcmBZyv z8YWO/KRo9Xvfuk6Crk/qNJIXecwFqU= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-583-gIoZIcZUN1WLrQ1bmp6zdQ-1; Tue, 06 Dec 2022 09:48:08 -0500 X-MC-Unique: gIoZIcZUN1WLrQ1bmp6zdQ-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 940CC38164DA; Tue, 6 Dec 2022 14:48:06 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.193.173]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7633B492B04; Tue, 6 Dec 2022 14:48:00 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: Andrew Morton , Hugh Dickins , John Hubbard , Jason Gunthorpe , Mike Rapoport , Yang Shi , Vlastimil Babka , Nadav Amit , Andrea Arcangeli , Peter Xu , linux-mm@kvack.org, x86@kernel.org, linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, loongarch@lists.linux.dev, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, David Hildenbrand , Richard Henderson , Ivan Kokshaysky , Matt Turner Subject: [PATCH mm-unstable RFC 02/26] alpha/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE Date: Tue, 6 Dec 2022 15:47:06 +0100 Message-Id: <20221206144730.163732-3-david@redhat.com> In-Reply-To: <20221206144730.163732-1-david@redhat.com> References: <20221206144730.163732-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221206_064812_410462_7C32C9EF X-CRM114-Status: GOOD ( 16.65 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by stealing one bit from the type. Generic MM currently only uses 5 bits for the type (MAX_SWAPFILES_SHIFT), so the stolen bit is effectively unused. While at it, mask the type in mk_swap_pte() as well. Note that 32bit alpha has 64bit PTEs but only 32bit swap entries. So the lower 32bit are zero in a swap PTE and we could have taken a bit in there as well. Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Matt Turner Signed-off-by: David Hildenbrand --- arch/alpha/include/asm/pgtable.h | 41 ++++++++++++++++++++++++++++---- 1 file changed, 37 insertions(+), 4 deletions(-) diff --git a/arch/alpha/include/asm/pgtable.h b/arch/alpha/include/asm/pgtable.h index 9e45f6735d5d..970abf511b13 100644 --- a/arch/alpha/include/asm/pgtable.h +++ b/arch/alpha/include/asm/pgtable.h @@ -74,6 +74,9 @@ struct vm_area_struct; #define _PAGE_DIRTY 0x20000 #define _PAGE_ACCESSED 0x40000 +/* We borrow bit 39 to store the exclusive marker in swap PTEs. */ +#define _PAGE_SWP_EXCLUSIVE 0x8000000000UL + /* * NOTE! The "accessed" bit isn't necessarily exact: it can be kept exactly * by software (use the KRE/URE/KWE/UWE bits appropriately), but I'll fake it. @@ -301,18 +304,48 @@ extern inline void update_mmu_cache(struct vm_area_struct * vma, } /* - * Non-present pages: high 24 bits are offset, next 8 bits type, - * low 32 bits zero. + * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that + * are !pte_none() && !pte_present(). + * + * Format of swap PTEs: + * + * 6 6 6 6 5 5 5 5 5 5 5 5 5 5 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3 + * 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 + * <------------------- offset ------------------> E <--- type --> + * + * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 + * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 + * <--------------------------- zeroes --------------------------> + * + * E is the exclusive marker that is not stored in swap entries. */ extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset) -{ pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; } +{ pte_t pte; pte_val(pte) = ((type & 0x7f) << 32) | (offset << 40); return pte; } -#define __swp_type(x) (((x).val >> 32) & 0xff) +#define __swp_type(x) (((x).val >> 32) & 0x7f) #define __swp_offset(x) ((x).val >> 40) #define __swp_entry(type, off) ((swp_entry_t) { pte_val(mk_swap_pte((type), (off))) }) #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) #define __swp_entry_to_pte(x) ((pte_t) { (x).val }) +#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE +static inline int pte_swp_exclusive(pte_t pte) +{ + return pte_val(pte) & _PAGE_SWP_EXCLUSIVE; +} + +static inline pte_t pte_swp_mkexclusive(pte_t pte) +{ + pte_val(pte) |= _PAGE_SWP_EXCLUSIVE; + return pte; +} + +static inline pte_t pte_swp_clear_exclusive(pte_t pte) +{ + pte_val(pte) &= ~_PAGE_SWP_EXCLUSIVE; + return pte; +} + #define pte_ERROR(e) \ printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e)) #define pmd_ERROR(e) \